This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This program aims to determine the structures of proteins involved in two distinct kinds of cellular signaling cascades in order to establish the mechanism and specificity of their interactions: Wnt growth factor signaling, which specifies cell fate during embryogenesis, tissue renewal in the adult, and is altered in many cancers;and G-protein coupled receptor signaling, specifically the beta2-adrenergic receptor, which responds to catecholamine ligands and has important roles in cardiovascular and pulmonary physiology. There are currently two projects with crystals that require synchrotron radiation. 1. Interactions of the Wnt co-receptor LRP6 with activating and inhibitory binding protein partners. 2. Activation of the beta2-adrenergic receptor, examining its structure bound to activating small-molecule.